Cassandra: disable two particularly slow metrics (#655)

Disabling these two metrics speeds up the scrape time dramatically on our Cassandra cluster - from around 20 seconds to 3 seconds. I think it's worth disabling these by default because it makes the JMX exporter much more usable with Cassandra and this trick isn't particularly obvious. Signed-off-by: Russ Garrett <[email protected]>
prometheus · Oct 9, 2024 · 8994941 · 8994941
1 parent aedf4de
commit 8994941
Showing 1 changed file with 8 additions and 2 deletions.
diff --git a/example_configs/cassandra.yml b/example_configs/cassandra.yml
@@ -1,8 +1,14 @@
 lowercaseOutputLabelNames: true
 lowercaseOutputName: true
 whitelistObjectNames: ["org.apache.cassandra.metrics:*"]
-# ColumnFamily is an alias for Table metrics
-blacklistObjectNames: ["org.apache.cassandra.metrics:type=ColumnFamily,*"]
+
+blacklistObjectNames:
+  # ColumnFamily is an alias for Table metrics
+  - "org.apache.cassandra.metrics:type=ColumnFamily,*"
+  # TotalDiskSpaceUsed and EstimatedPartitionCount slow down scraping significantly
+  - "org.apache.cassandra.metrics:*,name=TotalDiskSpaceUsed"
+  - "org.apache.cassandra.metrics:*,name=EstimatedPartitionCount"
+
 rules:
 # Generic gauges with 0-2 labels
 - pattern: org.apache.cassandra.metrics<type=(\S*)(?:, ((?!scope)\S*)=(\S*))?(?:, scope=(\S*))?, name=(\S*)><>Value